Odd numbers with exactly 4 palindromic prime factors (counted with multiplicity).

Terms

a(0) =81a(1) =135a(2) =189a(3) =225a(4) =297a(5) =315a(6) =375a(7) =441a(8) =495a(9) =525a(10) =625a(11) =693a(12) =735a(13) =825a(14) =875a(15) =1029a(16) =1089a(17) =1155a(18) =1225a(19) =1375a(20) =1617a(21) =1715a(22) =1815a(23) =1925a(24) =2401a(25) =2541a(26) =2695a(27) =2727a(28) =3025a(29) =3537